Take a terminal cutting of fiirm new growth. 2-4 inches ling 1 leaf at tip. apply 0.1 to 0.3%IBA (Rooting hormone) stick in well drained soil & mist. taking 21-50 days to root.
Keep in indirect light.

My sambac jasmine rooted in plain tap water in a glass tumbler. I picked a 2 month old stem that I pruned off the main plant. It took about 3 months from pruning to roots. As long as it stayed green and the water didn't cloud up, I left it alone. It formed calluses almost immediately, but no roots. I left it alone, topped off with more water when the level got low. Finally my patience paid off and I saw a tiny root emerging. Once the root popped out, it grew pretty fast - about an inch in a week. Then I potted it. I figure that once it warms up, it'll grow pretty fast. I have it indoors in a pot.

Whatever method you use, patience is key. I chose the water rooting method coz I could see what was happening.